Differences in soil properties influence floristic changes in the Veredas of the Brazilian Cerrado

The vereda (Brazilian savanna palm swamp) has a distinguishable flora and high floristic beta diversity. The factors that influence dissimilarities among vereda floras have not been clearly elucidated. Here we investigated how key physicochemical soil factors modulate the species composition of this vegetation. Soil and plants were sampled from three veredas, species composition and diversity were compared among them. To investigate the effects of soil physicochemical properties on species richness and cover of each vereda, we fitted a linear mixed-effect model. The plant assemblages in the veredas diverged in terms of species composition but converged in two dominant species graminoids. We found significant differences in soil properties among the veredas, except in texture. Soil properties had significant effects on species richness and cover as a whole, and on richness and relative cover for the individual growth forms. Potential cation-exchange capacity alone negatively affected species richness, especially of graminoids and subshrubs. The cation-exchange capacity of soils and its complex interactions with phosphorus and organic matter were found to be the main drivers of species occurrence and vegetation cover in the veredas. The distinct flora of veredas is controlled by the interaction of species and its growth forms with soil filters.